Temporal spatial information is considered as a favorable data source to comprehend the changes in the past. Since 20th century, higher accuracy maps and images based on the technique of surveying has appeared in Taiwan. However, in order to retrieve these spatial information from the historical images, image registration and rectification should be done. In this study, we present a methodology of processing multi-temporal datasets during the past hundred years by commercial software (SOCET GXP 4.0) and a block adjustment with affine transformation. The temporal datasets used in this study include: (1) 1904 and 1921 ancient topographic maps; (2)1947,1948 and 1970s historical aerial images; (3)1985-1989 economic planning and development topographic map; (4) 2009 satellite images; (5) 2010 ortho-images. The accuracy was also assessed. And we focused on the coastal zone of old Tainan city (about Anping nowadays). The land use are classified into 9 categories by manual interpretation and digitization on the temporal datasets. A transition matrix is also utilized to present the land use changes referring to some historical records.

Cloud covers present in optical satellite images generally limit the data usage and increase the difficulty of data analysis. Information reconstruction of could-contaminated images thus plays a fundamental step in data preprocessing. A method to accurately and consistently reconstruct information of cloud-contaminated pixels in multitemporal remote-sensing images is proposed in this study. By utilizing temporal correlation of multitemporal images, a patch-based information reconstruction that spatiotemporally segments a sequence of images into several patches with similar temporal variation is performed, and then information from cloud-free and high-similarity patches is cloned to their corresponding cloud-contaminated patches. In addition, a seam passing through homogenous regions is determined for a cloud-contaminated region to reduce radiometric inconsistency. A cloud-contaminated region is segmented into several patches and their corresponding cloud-free patches are determined by a quality assessment index, and the multi-patch information cloning is solved by an optimization process with a determined seam. These processes enable the proposed method to accurately and consistently reconstruct missing information in cloud areas. Qualitative analyses on sequences of images acquired by the Landsat-7 ETM+ sensor and a quantitative analysis on a simulated data are conducted to evaluate the proposed method. The experimental results the ability of our method to generate visually smoothing reconstruction results.

The intensity value on each image pixel is determined by the functions of incident illumination and reflection of ground objects. In fact, light cast on terrain objects such as buildings and trees would cause shadows and occlusion. It is hard to restore original textures and color information in shadow areas. Many detailed information is hidden or lost due to such problems. Moreover, false color tone, shape distortion and inaccurate image matching within shadow areas also infect image recognition. This paper proposes an algorithm for automatic shadow detection based on the principal component analysis(PCA). It is tested by using both RGB and HSI bands in order to determine a proper and suitable color space for shadow detection. Besides shadow detection, color restoration in shadow areas is an important issue, too. This paper also performs subjective and objective evaluation on both histogram matching method and the local statistics method for color restoration in shadow areas. Test results demonstrate satisfied quality for restored images in shadow area.

Abstract Taking advantage of spatial information technology, the efficiency of collecting data in the field and the data accuracy have been dramatically enhanced for geologists nowadays. In this research, by using UAVs (unmanned aerial vehicles) with a digital camera, and ultra-high accuracy ground control points, we produce ortho- and elevation images in order to recognize and analyze geological structures. We take a 750-meter-wide Dahan River riverbed near the Shihmen reservoir and a Dajia River cliff outcrop of the Sanyi active fault as examples to illustrate the usefulness of UAV for geologists. At the Dahan Riverbed, there are a series of left-lateral sense faults with orientation of N20°E. Furthermore, an S-shaped fold has been recognized with a 50-meter amplitude and 200-meter half-wavelength in the orthoimage. At the Dajia River cliff, a 980-meter-long elevation image has been produced. At least three fault branches can be recognized on the elevation image. They are labelled as F1, F2 and F3 from west to east in this Sanyi fault zone. F1 cutting into the modern gravelly layer has been acknowledged as the most active branch fault in the research area. F2 did not cut into the overlaid 70-meter-high terrace layer. It may be the fault branch with a maximum separation because the greenish grey sandstone of Kueichulin formation formed earlier than 4 million ago is not exposed west of F2 on the cliff. The hanging wall of F3 is composed of the greenish grey sandstone of Kueichulin formation and the footwall of F3 is composed of gravelly layer formed after 2 million years ago. The F3 is overlaid with regolith and vegetation. The results of the geologically structural analyze above all benefit from the images taken via UAV. Moreover, the GSD (ground sample distance) of the high-quality models presented in this study reaches 4 cm/pixel. With the accuracy of static GPS (global positioning system) reaches about 0.5cm in horizontal and 1cm in elevation. DSM accuracy is about in centimeters. To sum up, UAV-based photogrammetry with high accuracy ground control points, showing a high efficiency and high flexibility indispensable technology in the field survey for geologists.

Steve Coast created the OpenStreetMap (OSM) in 2004 in the United Kingdom. OSM is a community project in which everyone can participate. Active contributors can map out their neighborhoods and countries. However, the quality of the OSM is a critical topic. Combining the surveying technologies, such as control surveying, leveling, and Global Positioning System measurement with OSM will make it more accurate. This study integrates topographical surveying into the OSM. The case study was conducted in Tainan Park, Tainan City in July and August 2014. The maps from professional surveying were imported into the Java OSM Editor and the OSM was edited. A comparison between the OSM before and after editing shows that the surveying results enriched the OSM. The professional surveying results can be demonstrated by the OSM. The results also indicate that location, number, area, and shape of buildings and pool differ dramatically before and after the OSM editing.